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Commit 2342f332 authored by Nicolas Pitre's avatar Nicolas Pitre Committed by Pierre Ossman
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sdio: allow for mmc_claim_host to be aborted 



It is sometimes necessary to give up on trying to claim the host lock,
especially if that happens in a thread that has to be stopped.

While at it, fix the description for mmc_claim_host() which was wrong.

Signed-off-by: default avatarNicolas Pitre <npitre@mvista.com>
Signed-off-by: default avatarPierre Ossman <drzeus@drzeus.cx>
parent 55fe77a0

drivers/mmc/core/core.c

+16 −6
Original line number Diff line number Diff line
@@ -273,15 +273,20 @@ void mmc_set_data_timeout(struct mmc_data *data, const struct mmc_card *card) 
EXPORT_SYMBOL(mmc_set_data_timeout);



/**

 *	mmc_claim_host - exclusively claim a host

 *	__mmc_claim_host - exclusively claim a host

 *	@host: mmc host to claim

 *	@abort: whether or not the operation should be aborted

 *

 *	Claim a host for a set of operations.

 *	Claim a host for a set of operations.  If @abort is non null and

 *	dereference a non-zero value then this will return prematurely with

 *	that non-zero value without acquiring the lock.  Returns zero

 *	with the lock held otherwise.

 */

void mmc_claim_host(struct mmc_host *host)

int __mmc_claim_host(struct mmc_host *host, atomic_t *abort)

{

	DECLARE_WAITQUEUE(wait, current);

	unsigned long flags;

	int stop;



	might_sleep();
@@ -289,19 +294,24 @@ void mmc_claim_host(struct mmc_host *host) 
	spin_lock_irqsave(&host->lock, flags);

	while (1) {

		set_current_state(TASK_UNINTERRUPTIBLE);

		if (!host->claimed)

		stop = abort ? atomic_read(abort) : 0;

		if (stop || !host->claimed)

			break;

		spin_unlock_irqrestore(&host->lock, flags);

		schedule();

		spin_lock_irqsave(&host->lock, flags);

	}

	set_current_state(TASK_RUNNING);

	if (!stop)

		host->claimed = 1;

	else

		wake_up(&host->wq);

	spin_unlock_irqrestore(&host->lock, flags);

	remove_wait_queue(&host->wq, &wait);

	return stop;

}



EXPORT_SYMBOL(mmc_claim_host);

EXPORT_SYMBOL(__mmc_claim_host);



/**

 *	mmc_release_host - release a host

include/linux/mmc/core.h

+12 −1
Original line number Diff line number Diff line
@@ -114,7 +114,18 @@ extern int mmc_wait_for_app_cmd(struct mmc_host *, struct mmc_card *, 


extern void mmc_set_data_timeout(struct mmc_data *, const struct mmc_card *);



extern void mmc_claim_host(struct mmc_host *host);

extern int __mmc_claim_host(struct mmc_host *host, atomic_t *abort);

extern void mmc_release_host(struct mmc_host *host);



/**

 *	mmc_claim_host - exclusively claim a host

 *	@host: mmc host to claim

 *

 *	Claim a host for a set of operations.

 */

static inline void mmc_claim_host(struct mmc_host *host)

{

	__mmc_claim_host(host, NULL);

}



#endif